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RESEARCH ARTICLE Open Access

Translation and validation of the Koreanversion of the clinical frailty scale in olderpatientsRyoung-Eun Ko1†, Seong Mi Moon2†, Danbee Kang3,4, Juhee Cho3,4,5, Chi Ryang Chung1, Yunhwan Lee6,7,Yun Soo Hong8, So Hee Lee9, Jung Hee Lee10 and Gee Young Suh1,11*

Abstract

Background: Frailty is a multidimensional syndrome that leads to an increase in vulnerability. Previous studies havesuggested that frailty is associated with poor health-related outcomes. For frailty screening, the Clinical Frailty Scale(CFS) is a simple tool that is widely used in various translated versions. We aimed to translate the CSF into Koreanand evaluated its contents and concurrent validity.

Methods: Translations and back-translations of the CFS were conducted independently. A multidisciplinary teamdecided the final CFS-K. Between August 2019 and April 2020, a total of 100 outpatient and inpatient participantsaged ≥65 years were enrolled prospectively. The clinical characteristics were evaluated using the CFS-K. The CFS-Kscores were compared with those of other frailty screening tools using Pearson’s correlation coefficient andSpearman’s rank correlation. The area under curve (AUC) for identifying the Eastern Cooperative Oncology GroupPerformance Status (ECOG PS) grade 3 or more was calculated for the CFS-K and other screening tools.

Results: The mean age of the participants was 76.5 years (standard deviation [SD], 7.0), and 63 (63%) participantswere male. The mean CFS-K was 4.8 (SD, 2.5). Low body mass index (p = 0.013) and low score on the Koreanversion of the Mini-Mental State Examination (p < 0.001) were significantly associated with high CFS-K scores,except for those assigned to scale 9 (terminally ill). The CFS-K showed a significant correlation with other frailtyscreening tools (R = 0.7742–0.9190; p < 0.01), except in the case of those assigned to scale 9 (terminally ill). Incomparison with other scales, the CFS-K identified ECOG PS grade 3 or more with the best performance (AUC =0.99). Patients assigned to scale 9 on the CFS-K (terminally ill) had similar frailty scores to those assigned to scale 4(vulnerable) or 5 (mildly frail).

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* Correspondence: [email protected]†Ryoung-Eun Ko and Seong Mi Moon contributed equally to this work.1Department of Critical Care Medicine, Samsung Medical Center,Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu,Seoul 06351, Republic of Korea11Division of Pulmonary and Critical Care Medicine, Department of Medicine,Samsung Medical Center, Sungkyunkwan University School of Medicine,Seoul, Republic of KoreaFull list of author information is available at the end of the article

Ko et al. BMC Geriatrics (2021) 21:47 https://doi.org/10.1186/s12877-021-02008-0

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Conclusions: In conclusion, the CFS-K is a valid scale for measuring frailty in older Korean patients. The CFS-Kscores were significantly correlated with the scores of other scales. To evaluate the predictive and prognostic valueof this scale, further larger-scale studies in various clinical settings are warranted.

Keywords: Clinical frailty scale, Frailty, Translation, Validation, Korean

BackgroundFrailty is a multidimensional syndrome involving loss ofreserves (energy, physical ability, cognition, and health)accompanied by an increase in vulnerability to increaseddependency and/or mortality when exposed to a stressor[1, 2]. Frailty is either physical or psychological or acombination of both [2]. Physical frailty is characterizedby diminished strength and endurance and reducedphysiologic function [1] and associated with increasedhealth-related outcomes in older populations, includinghospitalization, nursing home admission, re-admission,and mortality [3–10]. Therefore, for physicians, frailtyscreening is useful for risk stratification, goal setting andadvanced care planning, and frailty-targeted interven-tions [1, 11–13].A recent consensus conference which was attended by

the international societies and experts in the area offrailty recommended screening for frailty in all olderpersons and individuals with significant weight loss dueto chronic disease [1]. They also suggested instrumentsfor several screening tests such as the Fatigue, Resist-ance, Ambulation, Illness, and Loss of weight (FRAIL)questionnaire, Cardiovascular Health Study (CHS) frailtyscreening, and Clinical Frailty Scale (CFS) [1, 14].Among them, the CFS is the most widely applied assess-ment tool [15]. The CFS is a simple, rapid screening testproposed by Rockwood and colleagues [2]. The CFS wasbased on the theoretical model of fitness, frailty, andfunction; it was developed as a grading tool with sevenscales in 2005 [2] and revised in 2008 to include a totalof nine scales. The CFS is composed of visual and writ-ten charts for frailty with nine graded pictures [2] and ittakes less than 5min to complete [14]. The CFS wasdeveloped to measure the frailty based on clinical judge-ment [2, 14], and studies have shown that CFS is usefulto predict clinical outcomes in various clinical settingssuch as emergency department, intensive care units orpostoperative [5, 16–19]. Because of its usefulness, theoriginal English version of the CFS has been translatedin different languages [12, 20, 21].In Korea, The Eastern Cooperative Oncology Group

Performance Status (ECOG PS) scale, the Koreanversion of FRAIL (K-FRAIL), Korean Cancer StudyGroup Geriatric Score (KG-7), and Korean Frailty Indexare commonly used to assess frailty due to lack of appro-priate measures [22–25]. However, these tools require

more time for completion than the CFS, and most arelimited to cancer patients. Herein, we aimed to validatethe Korean version of the CSF (CSF-K). Specifically, wetranslated the CSF into Korean and evaluated its con-tents validity. In addition, we also evaluate specificityand sensitivity of the CSF-K and concurrent validity bycomparing with other scales.

MethodsParticipantsWe prospectively enrolled 100 patients aged ≥65years who visited an outpatient clinic or were admit-ted to the general ward or intensive care units ofthe Samsung Medical Center and Samsung Chang-won Hospital between August 2019 and April 2020.The patients were eligible to participate if they ortheir guardians, who were closely involved in theircare, gave informed consent to measure frailty.Patients diagnosed with dementia were excluded.The Institutional Review Board of the SamsungMedical Center (IRB No. 2019–02–028-004) andSamsung Changwon Hospital (IRB No. 2019–06-003)approved this study, and each participant providedinformed written consent.

Translation of clinical frailty scale to KoreanOriginal CFS in English consists of a scale from 1 (veryfit) to 9 (terminally ill), which is scored by clinical judg-ment; hence, the last group is technically not frail [2](Fig. 1). To develop the CFS-K, we obtained copyrightpermission from Dr. Rockwood, who developed the ori-ginal CFS. Three bilingual experts translated the CFS toKorean independently; then, it was back translated toEnglish by three independent bilingual experts [26].After this process, a multidisciplinary team of experts,including intensivists, intensive care unit nurses, anexpert in geriatric medicine, behavioral scientists, andclinicians, reviewed and confirmed the instruments’ con-tent (Fig. 1). In addition, a pilot test with five patientsconfirmed the content validity of the scale (data notshown).

MeasurementsTo assess the baseline cognitive function, we used theKorean version of the Mini-Mental State Examination(K-MMSE) [27]. Other demographic and clinical

Ko et al. BMC Geriatrics (2021) 21:47 Page 2 of 8

information including comorbidity, admitted location,and primary reason for admission were obtained fromthe participants’ medical records.To examine the concurrent validity, we used the

ECOG PS, K-FRAIL scale, KG-7, and Korean FrailtyIndex [22–25, 28]. The ECOG PS scale is a measure-ment tool used to describe a patient’s level of function-ing from 0 to 5, with increasing scores indicatingincreasing levels of deterioration [22]. The K-FRAILscale is a screening tool for measuring frailty status usinga five-item questionnaire, which ranged 1 to 5, withincreasing scores indicating increasing frailty [23]. TheKG-7 is a screening tool for geriatric assessment usingseven items representing each domain of the geriatricassessment scale, which ranged 0 to 7 [24], with decreas-ing scores indicating increasing deterioration. TheKorean Frailty Index is an eight-item questionnaire thatmeasures frailty in older patients, with scores rangingfrom 0 to 8, and high scores indicating increasing levelsof deterioration [25].

Statistical methodsData analyses included descriptive statistics (frequencies,means, and standard deviations) and statistical analysesfor assessing frailty. In order to measure the CFS-K’sconcurrent validity, Pearson’s coefficients for correlationbetween CFS and the other scales including the KG-7,

K-FRAIL, and Korean Frailty Index, and Spearman’srank-order for correlation between CFS and ECOG PSwere computed. In addition, we calculated the sensitivityand specificity of identifying ECOG 3 or more using thearea under the curve (AUC). The performance foridentifying frailty was compared between CFS-K andthe K-FRAIL, KG-7, and Korean Frailty Index, withBonferroni’s correction to adjust for multiple compar-isons. For the analyses, KG-7 was recorded in reverseto achieve the same direction scores. We used thetwo way sided p-values to compare the AUC of CFS-K with AUC of other frailty screening tests. The sig-nificance level was set at 0.05. All analyses were per-formed using STATA version 15 (Stata Corp LP,College Station, TX, USA).

ResultsParticipant characteristicsThe participants’ characteristics are demonstrated inTable 1. A total 100 outpatient (n = 10, 10.0%) andinpatient (n = 90, 90.0%) participants were recruited attwo medical centers. The mean age of the study partici-pants was 75.6 years old and 63.0% were men. The meanbody mass index was 21.7 kg/m2 (standard deviation[SD], 3.5 kg/m2). Among the participants, the commoncomorbidity was chronic lung disease including chronicobstructive pulmonary disease, asthma, and interstitial

Fig. 1 Original and Korean versions of Clinical Frailty Scale


lung disease (44%), followed by hypertension (38%) andcancer (32%). For the 90 inpatients, the primary reasonfor admission was pneumonia (42.2%) followed bycancer-related management (24.4%). Of the 10 outpa-tients, 9 visited for pulmonary disease (90%), and onevisited for cardiovascular disease (10%). K-MMSE wasmeasured in 96 (96%) patients and the mean score ofthe K-MMSE was 22.2 (SD 7.2).

Characteristics by clinical frailty scale-KoreanAll of the participants completed the CFS-K, and themean score was 4.8 (SD, 2.5). The characteristics ofthe participants are grouped by CFS-K scale(Table 2). Except for patients assigned to scale 9(terminally ill), the mean age and proportion ofmales were different for each scale but without sig-nificance (P for trends 0.576 and 0.052, respectively).Body mass index was higher in patients assigned toscales 1 (very fit)–4 (vulnerable) than in thoseassigned to scales 5 (mildly frail)–8 (very severelyfrail), at a significant level (P for trend 0.013). TheK-MMSE data were obtained from 96 (96%) of allthe participants. The patients assigned to scale 1(very fit) had the highest (mean (standard deviation[SD])) K-MMSE score (28.7 (2.7)) and those assignedto scale 8 (very severely frail) had the lowest K-MMSE score (12.7(8.1)) with significant differenceacross the groups (P for trends < 0.001). The bodymass index of patients assigned to scale 9 (terminallyill) was higher than that of patients assigned to scale2 (well) and the K-MMSE score (21.0 (8.7)) ofpatients assigned to scale 6 (moderately frail) (18.9(5.9)) was higher than that of patients assigned toother scales.

Table 1 Characteristics of the study participants

Participants (N = 100)

Age (years) 75.6 (7.0)

Sex

Male 63 (63.0)

Female 37 (37.0)

Body mass index (kg/m2) 21.7 (3.5)

Comorbidity

Chronic lung disease 44 (44.0)

Hypertension 38 (38.0)

Cancer (oncology/hematology) 32 (32.0)

Diabetes 30 (30.0)

Cardiac disease (ischemic/vascular) 26 (26.0)

Cerebrovascular disease 17 (17.0)

Chronic kidney disease 11 (11.0)

Location

Outpatient 10 (10.0)

Inpatient 90 (90.0)

Primary admission cause in ward patients (N = 90)

Pneumonia 38 (42.2)

AE of underlying lung disease 11 (12.2)

Cardiac disease 14 (15.6)

Other infection 5 (5.6)

Cancer related problems 22 (24.4)

K-MMSE scorea 22.2 (7.2)

K-MMSE Korean version of the Mini-Mental State ExaminationValues are mean (SD) or number (%)aData were obtained from 96 (96%) participants

Table 2 Characteristics of the study participants as per Clinical Frailty Scale-Korean

1 Veryfit

2 Well 3 Managingwell

4Vulnerable

5 Mildlyfrail

6 Moderatelyfrail

7 Severelyfrail

8 Very severelyfrail

9Terminallyill

No. of patients 10 12 11 16 12 10 10 11 8

Age, years 73.2 (6.6) 78.7 (8.3) 74.3 (3.6) 72.8 (6.9) 76.7 (7.0) 77.8 (7.9) 76.9 (8.0) 75.5 (7.7) 75.8 (4.6)

Male, n 7 (70.0) 9 (75.0) 5 (45.5) 13 (81.2) 9 (75.0) 5 (50.0) 3 (30.0) 5 (45.5) 7 (87.5)

Body mass index (kg/m2)

23.5 (1.1) 21.6 (4.2) 22.8 (2.7) 22.4 (2.9) 20.3 (3.3) 21.2 (3.9) 21.0 (5.3) 19.8 (2.3) 23.0 (3.0)

K-MMSE

Mean (SD) 28.2 (2.7) 23.5 (7.9) 24.5 (4.0) 25.8 (3.5) 24.4 (3.6) 18.9 (5.9) 18.3 (7.3) 12.7 (8.1) 21 (8.7)

Median (IQR) 29 (27–30)

25 (23.5–27.5)

26 (22–28) 27 (25.5–28)

25.5 (22–27)

17 (16–25) 15.5 (13–26)

13 (7–20) 24 (21.5–25)

K-MMSE Korean version of the Mini-Mental State ExaminationValues in the Table are mean (SD), median (IQR), or number (%)P for trends for body mass index (p = 0.013) and K-MMSE (p < 0.001) were statistically significant. p for trends for age (p = 0.576) and sex (p = 0.052) were notsignificant. We excluded participants who were assigned to scale 9 (terminally ill) on the Clinical Frailty Scale-Korean


Correlation between frailty measures and clinical frailtyscale-Korean and validationThe frailty scores by CFS-K are summarized in Table 3.The patients assigned to scale 1 (very fit) had the highestKG7 score (6.7 (0.7)) and the lowest scores on the K-FRAIL (0.3 (0.5)) and Korean Frailty Index (1.2 (1.3)).All of the patients with CFS-K 1 (very fit) showed ECOGPS grade 0 (80%) or 1 (20%). In contrast, the patientsassigned to scale 8 (very severely frail) had the lowestKG7 score (0.8 (1.0)) and the highest score of K-FRAIL(3.7 (0.5)) and Korean Frailty Index (6.8 (1.1)). Patientswith CFS-K 8 showed ECOG PS grade 3 (30%) or 4(70%). Regarding patients assigned to scale 9 (terminallyill), the mean (SD) of KG7 (3.9 (2.0)), K-FRAIL (2.9(1.2)), and Korean frailty index (4.9 (1.5)) were similar tothose assigned to scale 4 (vulnerable) or 5 (mildly frail).The ECOG PS scores were inconsistent among patientsassigned to scale 9 (terminally ill). The CFS-K scores werepositively correlated with K-FRAIL (R = 0.8053) andKorean Frailty Index (R = 0.7742), ECOG PS (R = 0.9190)

scores and negatively correlated with KG-7 (R = − 0.8846)scores, except in the case of patients assigned to scale 9 onthe CSF-K (terminally ill).Regarding the receiver operating characteristic (ROC)

curve for identifying ECOG PS grade 3 or more, theCFS-K showed better performance (AUC = 0.99) thanthe KG-7 (AUC = 0.96; p = 0.08), K-FRAIL (AUC = 0.89;p < 0.01), and Korean Frailty Index (AUC 0.87; p < 0.01)(Fig. 2). In addition, the CFS-K has a sensitivity of 90.6%and a specificity of 97.0% for identifying ECOG PS grade3 or more.

DiscussionIn this study, we translated the CFS into Korean andevaluated the content and concurrent validity by com-paring it with other scales, namely the ECOG PS, K-FRAIL, KG-7, and Korean Frailty Index. The patientswere subjected all of the scales regardless of age or sex.High scores on the CFS-K were correlated to low bodymass index and low K-MMSE score. The CFS-K scores

Table 3 Performance of K-CFS against that of K-FRAIL, KG-7, Korean frailty index, and ECOG and Pearson’s correlations between K-CFS and other scales

1Veryfit

2 Well 3Managingwell

4Vulnerable

5 Mildlyfrail

6Moderatelyfrail

7 Severelyfrail

8 Veryseverely frail

9Terminallyill

Ra Rsa

K-FRAIL 0.8053* 0.8048*

Mean (SD) 0.3(0.5)

0.7(0.8)

0.8 (1.3) 1.3 (0.9) 3.3 (0.9) 3.8 (0.4) 3.5 (1.0) 3.7 (0.5) 2.9 (1.2)

Median (IQR) 0 (0–1)

0.5 (0–1)

0 (0–1) 1 (1–2) 3.5 (3–4) 4 (4–4) 4 (3–4) 4 (3–4) 3 (2–3.5)

KG-7 −0.8846* −0.8860*

Mean (SD) 6.7(0.7)

5.4(1.2)

5.5 (1.0) 4.3 (1.1) 3.4 (0.7) 1.8 (1.0) 1.0 (1.2) 0.8 (1.0) 3.9 (2.0)


5 (5–6.5)

6 (5–6) 4 (3–5) 3.5 (3–4) 1.5 (1–2) 1 (0–1) 1 (0–1) 3.5 (2–5.5)

Korean frailtyindex

0.7742* 0.7883*

Mean (SD) 1.2(1.3)

3.3(1.4)

2.2 (1.4) 4.3 (1.4) 5.8 (1.1) 5.2 (0.9) 6.2 (1.2) 6.8 (1.1) 4.9 (1.5)


3 (2–5) 3 (1–3) 4 (3–5.5) 6 (5.5–6) 5.5 (4–6) 6.5 (5–7) 7 (6–8) 5 (3.5–6)

ECOG PS 0.9190* 0.9184*

0 8(80.0)

3 (25.0) 2 (18.2) 1 (6.3) 0 0 0 0 1 (12.5)

1 2(20.0)

9 (75.0) 9 (81.8) 13 (81.3) 1 (8.3) 1 (8.3) 0 0 2 (25.0)

2 0 0 0 2 (12.5) 8 (66.7) 8 (66.8) 2 (20.0) 0 4 (50.0)

3 0 0 0 0 3 (25.0) 8 (80.0) 8 (80.0) 3 (30.0) 1 (12.5)

4 0 0 0 0 0 0 0 7 (70.0) 0

K-CFS Clinical Frailty Scale-Korean, K-FRAIL Korean version of the fatigue, resistance, ambulation, illness, and loss of weight, KG-7 Korean Cancer Study GroupGeriatric Score, ECOG PS Eastern Cooperative Oncology Group Performance StatusR and Rs were calculated using Pearson correlation and Spearman correlation, respectivelyP for trends for all the variables were statistically significant (p < 0.001)We excluded participants who were assigned to scale 9 (terminally ill) on the Clinical Frailty Scale-Korean*p < 0.01


were significantly correlated with the scores of otherscales and showed the best assessment of frailty.The CFS-K was found to be a useful screening tool of

frailty in Korean older patients. In this study, the newlytranslated Korean version of CFS recognized frailpatients more effectively than other scales. Previousstudies have suggested the CFS is a useful screening toolbased on clinical judgement for measuring frailty [8, 14].the translated version was also administered successfully.Moreover, the CFS-K correlated well with other scalesincluding the ECOG PS, K-FRAIL, KG-7, and KoreanFrailty Index, which are already used in clinical settings.Previous study showed that CFS has a sensitivity of56.0% and a specificity 98.4% for identifying frail accord-ing to the definition of CHS frailty screening. In thisstudy, the CFS-K also investigated concurrent validity.With the AUC of 0.99, a sensitivity 90.6%, and a specifi-city of 97.0%, the CFS-K showed excellent performancefor identifying ECOG PS grade 3 or more. As the CFShas predictive and prognostic features with regard toclinical outcomes in various clinical settings [5, 16, 17],the CFS-K could be a useful screening tool for frail olderin South Korea and also help provide optimalmanagement.Interestingly, the body mass index and K-MMSE score

showed significant differences across the CSF-K scales.The relationship between frailty and sarcopenia has beenreported in several studies [29, 30]; this study showedconsistent results. Since low body mass index is an

important risk factor of poor prognosis [31, 32], highscores on the CFS-K would be associated with poor clin-ical outcomes. The association between frailty and cog-nitive decline has been reported, and the results wereconsistent with previous findings [33, 34]. As importantclinical characteristics can be distinguished by quickassessment with the CFS-K, it can be a valuable tool forfrailty screening.The patients assigned to scale 9 (terminally ill) showed

unique characteristics. Because of the definition, forpatients who were not evidently frail but had less than 6months’ life expectancy, the scores of frailty indexeswere between scale 4 (vulnerable) and scale 5 (mildlyfrail) and the ECOG PS score also ranged from 0 to 3;their body mass index and K-MMSE scores were alsorelatively high. In this study, the patients diagnosed withadvanced solid or hematologic malignancy with hightumor burden were assigned to scale 9 (terminally ill).Nowadays, the life expectancy is increasing due toimprovement in cancer treatment, organ transplantation,and critical care with organ-supporting systems [35–39].Further studies regarding scale 9 (terminally ill) patients’clinical outcomes and prognosis are warranted.This study has some limitations. First, the validation of

the CFS-K was performed with a relatively small numberof participants. Second, this study included outpatientsand inpatients, not a community-based population.Moreover, only patients who gave consent were enrolled.These factors might have caused selection bias. Further

Fig. 2 Receiver operating characteristic (ROC) curves of frailty measures for identifying ECOG PS 3 or more (N = 92). In this figure, KG-7 wasrecorded as reverse to achieve the same direction scores. The participants assigned to CFS-K scale 9 (terminally ill) were excluded in this analysis.†P values were obtained to compare the ROC curves, and Bonferroni’s correction was used to adjust for multiple comparisons


large-scale studies with general population and patientsin various clinical settings are warranted.

ConclusionsIn conclusion, the CFS-K is a valid scale for measuringfrailty in older Korean patients. The CFS-K scores weresignificantly correlated with the scores of other scales.To evaluate the predictive and prognostic value of thisscale, further larger-scale studies in various clinicalsettings are warranted.

AbbreviationsFRAIL: Fatigue, Resistance, Ambulation, Illness, and Loss of weight;CHS: Cardiovascular Health Study; CFS: Clinical Frailty Scale; ECOG PS: EasternCooperative Oncology Group Performance Status; K-FRAIL: Korean version ofthe fatigue, resistance, ambulation, illness, and loss of weight; KG-7: KoreanCancer Study Group Geriatric Score; CFS-K: Korean version of Clinical FrailtyScale; K-MMSE: Korean version of the Mini-Mental State Examination;AUC: Area under the curve; SD: Standard deviation; ROC: Receiver operatingcharacteristic

AcknowledgmentsNot applicable.

Authors’ contributionsR.E.K.: Conceptualization, data curation, resources, formal analysis, writing oforiginal draft, and methodology. S.M.M.: Conceptualization, data curation,collection of resources, formal analysis, writing of original draft, andmethodology. S.H.L.: Data curation and reviewing/editing. J.H.L.: Datacuration and reviewing/editing. D.K.: Conceptualization, data curation, formalanalysis, writing of original draft, and methodology. J.C.: Conceptualization,data curation, formal analysis, writing of original draft, and methodology.C.R.C.: Conceptualization and review/editing. Y.L.: Conceptualization andreview/editing. Y.S.H.: Conceptualization, methodology, and reviewing/editing. G.Y.S.: Conceptualization, collecting of resources, data curation,formal analysis, writing of original draft, review/editing, methodology, andsupervision. All authors read and approved the final manuscript.

FundingThis research was supported by a grant of the Korea Health Technology R&Dproject through the Korea Health Industry Development Institute (KHIDI),funded by the Ministry of Health & Welfare, Republic of Korea (grant number:HI19C0481, HC19C0226). The funder had no role in the design of the study,the data collection and analysis, the interpretation of data and in writing themanuscript.

Availability of data and materialsThe data that support the findings of this study are available on requestfrom the corresponding author. The data are not publicly available due toprivacy or ethical restrictions.

Ethics approval and consent to participateThe Institutional Review Board of the Samsung Medical Center (IRB No.2019–02–028-004) and Samsung Changwon Hospital (IRB No. 2019–06-003)approved this study, and each participant provided informed writtenconsent.

Consent for publicationNot applicable.

Competing interestsThe authors declare that they have no competing interests.

Author details1Department of Critical Care Medicine, Samsung Medical Center,Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu,Seoul 06351, Republic of Korea. 2Division of Pulmonary and Critical CareMedicine, Department of Medicine, Samsung Changwon Hospital,

Sungkyunkwan University School of Medicine, Changwon, Republic of Korea.3Center for Clinical Epidemiology, Samsung Medical Center, Seoul, Republicof Korea. 4Department of Clinical Research Design and Evaluation, SAIHST,Sungkyunkwan University, Seoul, Republic of Korea. 5Department ofEpidemiology, Johns Hopkins University Bloomberg School of Public Heath,Baltimore, MD, USA. 6Department of Preventive Medicine & Public Health,Ajou University School of Medicine, Suwon, Republic of Korea. 7Institute onAging, Ajou University Medical Center, Suwon, Republic of Korea.8Departments of Epidemiology and Medicine, and Welch Center forPrevention, Epidemiology, and Clinical Research, Johns Hopkins UniversityBloomberg School of Public Health, Baltimore, MD, USA. 9Outpatient NursingTeam, Samsung Medical Center, Seoul, Republic of Korea. 10Medical IntensiveCare Unit, Samsung Medical Center, Seoul, Republic of Korea. 11Division ofPulmonary and Critical Care Medicine, Department of Medicine, SamsungMedical Center, Sungkyunkwan University School of Medicine, Seoul,Republic of Korea.

Received: 6 September 2020 Accepted: 4 January 2021

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AbstractBackgroundMethodsResultsConclusions

BackgroundMethodsParticipantsTranslation of clinical frailty scale to KoreanMeasurementsStatistical methods

ResultsParticipant characteristicsCharacteristics by clinical frailty scale-KoreanCorrelation between frailty measures and clinical frailty scale-Korean and validation

DiscussionConclusionsAbbreviationsAcknowledgmentsAuthors’ contributionsFundingAvailability of data and materialsEthics approval and consent to participateConsent for publicationCompeting interestsAuthor detailsReferencesPublisher’s Note

translation and validation of the korean version of the clinical ......reserves (energy, physical...

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